I'm working on a 61FLH that was recently bought in Arkansas. It looks like someone started a serious restoration project and at some point changed dedication level & just got it ready for sale.
When I first saw the bike it was so far out of tune it would only runs seconds before fouling the plugs. When it did start it was usually sumped & puked oil from the Primary. I pulled the outer cover, never expecting a belt drive. The oil was coming
from the Sprocket Shaft, the belt was still clean & dry. (it IS vented behind the primary with a modified early breather)
The belt is the same one pictured in Mr Mach1's post, and brand spanking new. The problem is, the belt was as tight as the top string on a guitar. no twist or deflection possible.
Also, it has stamped flanges to keep the belt from walking, the inside flange was loose & would spin behind the pulley, and had been scraping on the sprocket bearing nut. There were no shims behind it.
So I'm getting close to starting the bike. I've adjusted the dual points (the rear set was not even tightened down to the plate when purchased) Installed one of Tom Cotten's floats & a needle & seat from my stash (it had a rubber tipped needle)
I mocked up the belt drive last night, one medium shim from a kit purchased was installed & when tightened, the inside deflector/flange is tight & does not make contact with the nut or case. but the belt is way too tight for me. No deflection
(maybe 3/8") and hard to twist any at all. But I do have it staying in the center of the pulley kicking 10-20 times thru w/ no plugs installed.
1) Do we run it this tight & hope it will stretch quickly?
2) I don't want to) Do we extend the slots in the trans mounting plate 1/8" to 3/16" (& the 5th mount too)

drinner-okc wrote:I'm working on a 61FLH that was recently bought in Arkansas. It looks like someone started a serious restoration project and at some point changed dedication level & just got it ready for sale.
When I first saw the bike it was so far out of tune it would only runs seconds before fouling the plugs. When it did start it was usually sumped & puked oil from the Primary. I pulled the outer cover, never expecting a belt drive. The oil was coming
from the Sprocket Shaft, the belt was still clean & dry. (it IS vented behind the primary with a modified early breather)
The belt is the same one pictured in Mr Mach1's post, and brand spanking new. The problem is, the belt was as tight as the top string on a guitar. no twist or deflection possible.
Also, it has stamped flanges to keep the belt from walking, the inside flange was loose & would spin behind the pulley, and had been scraping on the sprocket bearing nut. There were no shims behind it.
So I'm getting close to starting the bike. I've adjusted the dual points (the rear set was not even tightened down to the plate when purchased) Installed one of Tom Cotten's floats & a needle & seat from my stash (it had a rubber tipped needle)
I mocked up the belt drive last night, one medium shim from a kit purchased was installed & when tightened, the inside deflector/flange is tight & does not make contact with the nut or case. but the belt is way too tight for me. No deflection
(maybe 3/8") and hard to twist any at all. But I do have it staying in the center of the pulley kicking 10-20 times thru w/ no plugs installed.
1) Do we run it this tight & hope it will stretch quickly?
2) I don't want to) Do we extend the slots in the trans mounting plate 1/8" to 3/16" (& the 5th mount too)

Thanks for any & all suggestions.
drinner

I answered your question in the other thread, but basically this is what was done to my '61 Pan with BDL belt drive primary when I got it. Seems like I've read where others have said they had to do the same.

I didn't have to elongate the holes in my transmission plate, but I did have to grind just a smidge off the trans plate front mounting bolts to allow the transmission to slide all the way forward. I also aligned the flats so they were parallel with the front of the transmission case. This was with a Primo 1-1/2", 8mm belt drive. With my SuperMax SilentDrive the transmission sits about 1/2 way between front/back in the slots.

DO NOT run with a tight belt. Belts stretch very little. One of the fast ways to snap a belt is to run it tight.

I just installed a new BDL belt drive on my 62 and the bolts are about 3/8" from the rear. It has about 1/2" slack and works well. Do you know the maker of the belt or kit?
If I can be of help let me know.
Dave Beck
Elk City, Oklahoma

caschnd1 wrote:I didn't have to elongate the holes in my transmission plate, but I did have to grind just a smidge off the trans plate front mounting bolts to allow the transmission to slide all the way forward. I also aligned the flats so they were parallel with the front of the transmission case. This was with a Primo 1-1/2", 8mm belt drive. With my SuperMax SilentDrive the transmission sits about 1/2 way between front/back in the slots.

DO NOT run with a tight belt. Belts stretch very little. One of the fast ways to snap a belt is to run it tight.

-Craig

Yeah,I dont know what kind of quality control these belt companys have but this is rediculas.I have a 11mm primo and my transmission sits about a good inch behind the front plate mount bolts.

I don't think it's quality control, it's parts selection. My custom pan had a Primo and it did have a lot of miles on it & wear, but the trans was adjusted about 2/3rds the way back.
On the CAIMag site I was told BDL makes a clutch shell with one less cog. That alone would move the tranny back 4MM (I hate Metrics but that's about 3/32")
The closest Gates belt available is 8 cogs longer (8x8MM or 8x3/8") so that's way too much. I wish it was one less tooth on the motor sprocket!

Thanks for all the help. My Primo is out where the bike is. That may be our best option at this point. Or something called a chain?

Well there shouldnt be any difference between a BDL setup and a PRIMO setup because all knuckles and pans are spaced the same.The measurement between the shafts are the same.Primary chains are the same from 36-84.Theres no excuse.Somebody in those companys doesnt know how to measure.

I’m having the same problem putting a brand new BDL 8mm 1 1/2” belt drive in an enclosed primary with a brand new transmission and new tranny plate on a 1950 Panhead. The transmission is all the way forward to where it’s touching the center post and the belt is super tight. I’ve seen other people with the same problem but don’t understand why? Someone suggested getting a Bullseye drive belt that they are a little longer so I just ordered one but I was just wondering why some people have no problems and others do, is it that the frames are the issue or ?

I ditched my BDL for a 1950 Panhead for the same reason, too tight, and went with a Suept Max Silent Drive with no regrets other than the fact that Super Max is no longer servicing their customers since the founder died.
....RooDog....